package me.zhangsanfeng.gpss.common.utils;

import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.Validate;

/**
 * 反射工具类. 提供调用getter/setter方法, 访问私有变量, 调用私有方法, 获取泛型类型Class, 被AOP过的真实类等工具函数.
 */
// 压制警告，即去除警告
@SuppressWarnings("rawtypes")
@Slf4j
public class ReflectionUtil{
    private static final String SETTER_PREFIX="set";
    private static final String GETTER_PREFIX="get";
    private static final String CGLIB_CLASS_SEPARATOR="$$";

    /**
     * 调用Getter方法. 支持多级，如：对象名.对象名.方法
     */
    public static Object invokeGetter(Object obj,String propertyName){
        Object object=obj;
        for(String name:StringUtils.split(propertyName,".")){
            String getterMethodName=GETTER_PREFIX+StringUtils.capitalize(name);
            object=invokeMethod(object,getterMethodName,new Class[]{},new Object[]{});
        }
        return object;
    }

    /**
     * 调用Setter方法, 仅匹配方法名。 支持多级，如：对象名.对象名.方法
     */
    public static void invokeSetter(Object obj,String propertyName,Object value){
        Object object=obj;
        String[] names=StringUtils.split(propertyName,".");
        for(int i=0;i<names.length;i++){
            if(i<names.length-1){
                String getterMethodName=GETTER_PREFIX+StringUtils.capitalize(names[i]);
                object=invokeMethod(object,getterMethodName,new Class[]{},new Object[]{});
            }else{
                String setterMethodName=SETTER_PREFIX+StringUtils.capitalize(names[i]);
                invokeMethodByName(object,setterMethodName,new Object[]{value});
            }
        }
    }

    /**
     * 直接读取对象属性值, 无视private/protected修饰符, 不经过getter函数.
     */
    public static Object getFieldValue(final Object obj,final String fieldName){
        Field field=getAccessibleField(obj,fieldName);
        if(field==null){
            throw new IllegalArgumentException("Could not find field ["+fieldName+"] on target ["+obj+"]");
        }
        Object result=null;
        try{
            result=field.get(obj);
        }catch(IllegalAccessException e){
            log.error("不可能抛出的异常{}",e.getMessage());
        }
        return result;
    }

    /**
     * 直接设置对象属性值, 无视private/protected修饰符, 不经过setter函数.
     */
    public static void setFieldValue(final Object obj,final String fieldName,final Object value){
        Field field=getAccessibleField(obj,fieldName);
        if(field==null){
            throw new IllegalArgumentException("Could not find field ["+fieldName+"] on target ["+obj+"]");
        }
        try{
            field.set(obj,value);
        }catch(IllegalAccessException e){
            log.error("不可能抛出的异常:{}",e.getMessage());
        }
    }

    /**
     * 直接调用对象方法, 无视private/protected修饰符. 用于一次性调用的情况，否则应使用getAccessibleMethod()函数获得Method后反复调用. 同时匹配方法名+参数类型，
     */
    public static Object invokeMethod(final Object obj,final String methodName,
            final Class<?>[] parameterTypes,
            final Object[] args)
    {
        Method method=getAccessibleMethod(obj,methodName,parameterTypes);
        if(method==null){
            throw new IllegalArgumentException("Could not find method ["+methodName+"] on target ["+obj+"]");
        }
        try{
            return method.invoke(obj,args);
        }catch(Exception e){
            throw convertReflectionExceptionToUnchecked(e);
        }
    }

    /**
     * 直接调用对象方法, 无视private/protected修饰符， 用于一次性调用的情况，否则应使用getAccessibleMethodByName()函数获得Method后反复调用.
     * 只匹配函数名，如果有多个同名函数调用第一个。
     */
    public static Object invokeMethodByName(final Object obj,final String methodName,final Object[] args){
        Method method=getAccessibleMethodByName(obj,methodName);
        if(method==null){
            throw new IllegalArgumentException("Could not find method ["+methodName+"] on target ["+obj+"]");
        }
        try{
            return method.invoke(obj,args);
        }catch(Exception e){
            throw convertReflectionExceptionToUnchecked(e);
        }
    }

    /**
     * 循环向上转型, 获取对象的DeclaredField, 并强制设置为可访问. 如向上转型到Object仍无法找到, 返回null.
     */
    public static Field getAccessibleField(final Object obj,final String fieldName){
        Validate.notNull(obj,"object can't be null");
        Validate.notBlank(fieldName,"fieldName can't be blank");
        for(Class<?> superClass=obj.getClass();superClass!=Object.class;superClass=superClass
                .getSuperclass())
        {
            try{
                Field field=superClass.getDeclaredField(fieldName);
                makeAccessible(field);
                return field;
            }catch(NoSuchFieldException e){// NOSONAR
                // Field不在当前类定义,继续向上转型
                continue;// new add
            }
        }
        return null;
    }

    /**
     * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问. 如向上转型到Object仍无法找到, 返回null. 匹配函数名+参数类型。 用于方法需要被多次调用的情况.
     * 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
     */
    public static Method getAccessibleMethod(final Object obj,final String methodName,
            final Class<?>...parameterTypes)
    {
        Validate.notNull(obj,"object can't be null");
        Validate.notBlank(methodName,"methodName can't be blank");
        for(Class<?> searchType=obj.getClass();searchType!=Object.class;searchType=searchType
                .getSuperclass())
        {
            try{
                Method method=searchType.getDeclaredMethod(methodName,parameterTypes);
                makeAccessible(method);
                return method;
            }catch(NoSuchMethodException e){
                // Method不在当前类定义,继续向上转型
                continue;// new add
            }
        }
        return null;
    }

    /**
     * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问. 如向上转型到Object仍无法找到, 返回null. 只匹配函数名。 用于方法需要被多次调用的情况.
     * 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
     */
    public static Method getAccessibleMethodByName(final Object obj,final String methodName){
        Validate.notNull(obj,"object can't be null");
        Validate.notBlank(methodName,"methodName can't be blank");
        for(Class<?> searchType=obj.getClass();searchType!=Object.class;searchType=searchType
                .getSuperclass())
        {
            Method[] methods=searchType.getDeclaredMethods();
            for(Method method:methods){
                if(method.getName().equals(methodName)){
                    makeAccessible(method);
                    return method;
                }
            }
        }
        return null;
    }

    /**
     * 改变private/protected的方法为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。
     */
    public static void makeAccessible(Method method){
        if((!Modifier.isPublic(method.getModifiers())||!Modifier.isPublic(method.getDeclaringClass()
                .getModifiers()))
                &&!method.isAccessible())
        {
            method.setAccessible(true);
        }
    }

    /**
     * 改变private/protected的成员变量为public，尽量不调用实际改动的语句，避免JDK的SecurityManager抱怨。
     */
    public static void makeAccessible(Field field){
        if((!Modifier.isPublic(field.getModifiers())||!Modifier.isPublic(field.getDeclaringClass()
                .getModifiers())||Modifier
                        .isFinal(field.getModifiers()))&&!field.isAccessible())
        {
            field.setAccessible(true);
        }
    }

    /**
     * 通过反射, 获得Class定义中声明的泛型参数的类型, 注意泛型必须定义在父类处 如无法找到, 返回Object.class. eg. public UserDao extends HibernateDao
     * <Users>
     * @param clazz The class to introspect
     * @return the first generic declaration, or Object.class if cannot be determined
     */
    @SuppressWarnings("unchecked")
    public static <T> Class<T> getClassGenricType(final Class clazz){
        return getClassGenricType(clazz,0);
    }

    /**
     * 通过反射, 获得Class定义中声明的父类的泛型参数的类型. 如无法找到, 返回Object.class. 如public UserDao extends HibernateDao<Users,Long>
     * @param clazz clazz The class to introspect
     * @param index the Index of the generic ddeclaration,start from 0.
     * @return the index generic declaration, or Object.class if cannot be determined
     */
    public static Class getClassGenricType(final Class clazz,final int index){
        Type genType=clazz.getGenericSuperclass();
        if(!(genType instanceof ParameterizedType)){
            log.warn(clazz.getSimpleName()+"'s superclass not ParameterizedType");
            return Object.class;
        }
        Type[] params=((ParameterizedType)genType).getActualTypeArguments();
        if(index>=params.length||index<0){
            log.warn("Index: "+index+", Size of "+clazz.getSimpleName()+"'s Parameterized Type: "
                    +params.length);
            return Object.class;
        }
        if(!(params[index] instanceof Class)){
            log.warn(clazz.getSimpleName()+" not set the actual class on superclass generic parameter");
            return Object.class;
        }
        return (Class)params[index];
    }

    public static Class<?> getUserClass(Object instance){
        Validate.notNull(instance,"Instance must not be null");
        Class clazz=instance.getClass();
        if(clazz!=null&&clazz.getName().contains(CGLIB_CLASS_SEPARATOR)){
            Class<?> superClass=clazz.getSuperclass();
            if(superClass!=null&&!Object.class.equals(superClass)){
                return superClass;
            }
        }
        return clazz;
    }

    /**
     * 将反射时的checked exception转换为unchecked exception.
     */
    public static RuntimeException convertReflectionExceptionToUnchecked(Exception e){
        if(e instanceof IllegalAccessException||e instanceof IllegalArgumentException
                ||e instanceof NoSuchMethodException)
        {
            return new IllegalArgumentException(e);
        }else if(e instanceof InvocationTargetException){
            return new RuntimeException(((InvocationTargetException)e).getTargetException());
        }else if(e instanceof RuntimeException){
            return (RuntimeException)e;
        }
        return new RuntimeException("Unexpected Checked Exception.",e);
    }
}
